1. Field of the Invention
The present general inventive concept relates to an image projection apparatus, and more particularly, to an image projection apparatus having a duct and a fan to cool each of elements of the image projection apparatus, such as a lamp or the like.
2. Description of the Related Art
FIG. 1 is a plane view schematically showing a structure of a conventional image projection apparatus. A lamp 20, a color wheel 21, a digital mirror device (DMD) 22, and a projection lens 23 are shown in FIG. 1. The lamp 20, the color wheel 21, the DMD 22, and the projection lens 23 constitute an optical system for projecting an image. Reference numeral 30 denotes a power supply unit (PSU), and reference numeral 31 denotes a ballast for operating the lamp 20. Reference numeral 10 denotes a housing, and air vents 11, 12, 13, and 14 through which the air comes in and out are formed in the housing 10.
The lamp 20 radiates white light. The color wheel 21 includes a color filter through which each of red light, blue light, and green light passes selectively and which is rotatably installed before the lamp 20. When the white light irradiated by the lamp 20 passes through the color wheel 21, the white light is changed into monochromatic lights, such as red light, blue light or green light. The DMD 22 modulates the monochromatic lights passing through the color wheel 21 according to image data input from a control board (not shown). Modulated light is projected by the projection lens 23 on a screen (not shown).
Elements that need to be cooled to drive the image projection apparatus are the lamp 20 and the PSU 30, and if necessary, the DMD 22, the ballast 31, and the color wheel 21 can also be cooled. Four cooling fans 41, 42, 43, and 44 are shown in FIG. 1. The cooling fan 41 cools the lamp 20. The cooling fan 42 cools the ballast 31. The cooling fan 43 is installed to flow the air from the DMD 22 to the PSU 30 and cools both the DMD 22 and the PSU 30. The fan 44 cools the color wheel 21.
In the conventional image projection apparatus shown in FIG. 1, an additional fan for each of elements that need to be cooled is installed. Of course, a desired cooling performance can be obtained using the conventional image projection apparatus having the above structure. However, in the conventional image projection apparatus shown in FIG. 1, since a plurality of fans are installed to absorb and exhaust the air separately, paths through which the air comes in and out become complicated. Thus, it is difficult to effectively install the air vents 11, 12, 13, and 14. In addition, the air flowing through each fan collides with the housing 10. As such, a cooling efficiency may be lowered. In addition, the plurality of fans, which are separated from the complicated air-flow paths, may cause noise.